High-school girl Yui found a mysterious boy lying unconscious on the beach. This mysterious boy can't remember where he is from, only that his name is "Sid." After a confrontation with the locals, they discover that Sid is one of the human weaponry developed by the Japanese government, known as "Uncanny Brains" or UB. As the powers of the UB unfold before them, will Sid's arrival on this island spell doom for Yui and her friends?